In subsea well installations, a longitudinally extending flowline has an end which is brought into axial alignment with another flowline or fluid conducting pipe for interconnection of such lines and for providing a fluid tight seal connection. In some installations, one or both of the fluid conducting lines are axially movable relative to the other to bring the ends of the lines into close proximity, coupling the ends together, and providing a fluid tight seal at the coupling. In some underwater conditions, it is often difficult to move a flowline laid on the sea floor in an axial direction to bring its connector end into proximity with the connector end of a line to which it is to be connected because of the weight of the flowline, possible embedment of the flowline in the sea floor, or frictional resistance of the flowline with the sea floor. In subsea stations, end to end positioning of fluid conducting lines with precise axial alignment is often difficult to achieve; out of axial alignment conditions may prevent proper coupling and fluid tight sealing at the coupling.
Prior proposed fluid conducting line connecting devices have been actuated by fluid pressure and the fluid pressure has been relied upon to maintain the sealed relation of the coupling or connection. In the event fluid pressure was not maintained or there was a partial failure of the desired fluid pressure, the connecting device may leak at the sealing surfaces. Leakage of production or hydrocarbon fluids into the sea water is undesirable not only because of loss of production fluid, but also because of environmental pollution.
A flowline pipe end provided with a rotatable connector member has been moved laterally onto a support and then mechanical gear means associated therewith to move the rotatable connector axially into sealed relationship with a surface on a wellhead. See U.S. Pat. Nos. 3,502,354 and 3,593,408.